This disclosure relates to polysiloxane copolymers, thermoplastic compositions comprising these, methods of manufacture, and articles and uses thereof.
Plastic materials are widely used for fabricating components used in the interior of vehicles designed to move large numbers of people (e.g., commercial aircraft, ships, and trains). It is desirable for such materials, particularly where they are used in aircraft, to have excellent flame retardant properties and to release only low levels of heat and smoke when exposed to a flame. According to the Federal Aviation Regulations (FAR), specific flame retardant properties of interest for plastic components used in the interior of aircraft include at minimum a low heat release rate (referred to as the OSU 65/65 standard), low smoke density, and low toxicity of combustion products. In the event of a fire, components made from materials having these properties can increase the amount of time available that the passengers would have to escape, provide for better visibility during a fire, and reduce the toxicity of the emissions. Plastic materials that are useful in such applications generally must also have good processability for forming the components, and desirable physical properties such as surface finish, toughness to minimize the propensity of the parts to crack during use or secondary operations, weatherability, and transparency where desired.
In addition, it is desirable for these materials to have an intrinsic flame retardance that may be enhanced by addition of flame retardants. Plastic materials that meet such criteria desirably have flame retardant properties that are improved over the flame retardant properties of typical commercially available thermoplastic compositions.
Isophthalate-terephthalate-resorcinol (ITR) based polyarylate copolymers can possess many of these desired features, including toughness, transparency, and weatherability. ITR based polyarylate copolymers can have desirable thermal flow properties and are useful in a variety of manufacturing processes. In addition, ITR based polyarylate copolymers can have desirable solubility properties for the manufacture of polyarylate copolymers on a commercial scale using interfacial polymerization techniques. These polymerization techniques allow synthetic flexibility and composition specificity toward the synthesis of polyarylate copolymers with a target molecular weight and molecular composition.
There accordingly remains a need in the art for polyarylates having good intrinsic heat release rate performance, and low haze for use in thermoplastic compositions. In addition, the polyarylates may have good melt stability, solubility, and ductility. The thermoplastic compositions prepared therefrom also desirably have good color capability, weatherability, and gloss retention.